The term 'spiral-horned antelope' refers to four species of African antelopes: the ELAND (5 letters), KUDU (4 letters), NYALA (5 letters), and ADDAX (5 letters). These animals are characterized by their long, spiral horns and are found in savanna and woodland habitats. The ELAND is the largest of the spiral-horned antelopes, while the KUDU is the second largest. The NYALA is a medium-sized antelope with a reddish-brown coat and white stripes, and the ADDAX is a pale-colored antelope with long, twisted horns.